/*
 * @作者: 沙昊
 * @邮箱: shahao@zju.edu.cn
 * @功能: 
 * @包含算法: 
 * Copyright (c) 2023 by 沙昊, All Rights Reserved. 
 */

struct ListNode {
    int val;
    ListNode* next;
    ListNode(int x): val(x),next(NULL){}
};

ListNode* temp = new ListNode(0);


